No, he dies before the summon ever triggers. At the time, I had found it more difficult to survive long enough to use the damage boosts. He has only 1500 HP and a little shifting defense. Frankly, I was worried far more about his offensive capability taking me out than about killing him.

Oh, and when I said that I never made it to "Underworld Bond", I meant it's charm never triggered. I don't believe that summon has a name.

Of course you should drop all/most EAs, but if you're having exhaustion problems getting there, using self-stun actions will help. Of course if he's killing you, self stun will make it worse. Ongoing debuffs are easier than armor/ward, but either can be done (as tab showed me with a paladin).